1. Field of the Invention
The present invention relates to the field of seating the beads of a tubeless tire to a rim.
2. The Prior Art
The present invention relates to an improved apparatus for creating an airtight seal between the beads of a tubeless tire and a rim. The present invention is directed to an apparatus that generates a pneumatic pulse and directs the pulse in a manner to impart momentum to a bead and inject air into the tire, thereby setting a bead of a tubeless tire to a rim.
As shown in the prior art, one of the difficulties presented in changing tubeless tires is establishing the initial airtight seal between the beads of the tire and the bead-seating surfaces of the rim on which it is to be mounted. An uninflated tire has an open space or gap between the bead and the bead-seating surface of the rim, which is often so large that air seeps through the gap during inflation. This large gap inhibits the tire's ability to hold air, thereby preventing it from expanding so as to reduce the size of the gap. Heavy truck tires especially encounter this problem because the stiffness of the tires prevents sufficient reduction of the gap for seating to occur.
A number of different tools have been used to attempt to seat the beads of a tubeless tire. For example, mechanical straps or hoops have been used which squeeze the tire along the circumference of its tread and thereby force a bead upward toward the bead-seating surface as shown in U.S. Pat. No. 3,578,059, issued to J. Uhen on May 11, 1971. Additionally, pneumatic tools have been used that inject a narrow jet or on a circular curtain of high pressure air between a bead and the bead-seating surface as shown in U.S. Pat. No. 3,866,654, issued to V. Duquesne on Feb. 18, 1975.
Another type of pneumatic tool that has been used is shown in U.S. Pat. No. 5,072,764, which uses a single high energy pulse of air to produce a bead motion and internal pressure wave that cooperate to cause the contact between the bead and the rim to progress dynamically from one end of the bead to the other. However, this device fails to recognize that its discharge nozzle restricts airflow and the valve used to discharge the air flow reduces the effectiveness of the apparatus because it retards the rise time of the pulse of air. Additionally, the device recognizes the importance of stabilizing the rim prior to actuation of the device. However, this apparatus contemplates use of a rim support block, which is independent of the device and therefore must be hauled along with the device.
Another pneumatic tool is the one disclosed in U.S. Pat. No. 5,456,302 which makes use of a piston that is releasably sealed against an outlet of an air tank. Although this device provides for increased pressure rise time, it is susceptible to small air leaks, has an appreciable kickback, is expensive to manufacture, and does not contemplate supporting the rim on the tire prior to actuating the device.
Yet another pneumatic tool is described in U.S. Pat. No. 6,179,033 which makes use of a quick fill/release port to discharge the pressurized air. However, the quick fill/release port is susceptible to leakage and will discharge the air tank completely within an hour or so. This makes the device unsuitable for use over an extended period of time. For example, tow truck operators that have to travel an extended amount of time or a trucker who wishes to travel with the device over an extended haul will find this device unsuitable for use. Additionally, this device does not contemplate supporting the rim on the tire prior to actuating the device.